This project proposes to examine the effectiveness of several research-driven methods for improving the reading abilities of struggling adolescent readers. To that end, three approaches to reading instruction, each based on programs with demonstrated success in helping elementary school students, will be compared as interventions for adolescents whose word-reading levels are in the low-intermediate range (corresponding roughly to the reading levels of children in the second through sixth grades). Participants will complete pre-intervention, post-intervention and follow-up behavioral testing and functional magnetic resonance (fMRI) scanning. Initial cognitive and neurobiological profiles as well as relevant changes over time for these students will be compared to untreated adolescents with reading difficulties, younger reading-level matched controls, and age-matched controls. By investigating the cognitive and neurobiological underpinnings of these students' reading difficulties and by identifying effective and efficient methods of intervention for this population, we aim to further the understanding of adolescent literacy in ways that will have important theoretical and practical implications. Specifically, this research aims to (1) describe the cognitive, linguistic, and neurobiological factors that are associated with reading difficulties in adolescence; (2) conduct rigorous, experimental field trials of three promising, research-based instructional programs designed to raise the word reading skills, fluency, and text processing abilities of adolescents with low-intermediate reading levels; (3) to use pre- and post-intervention fMRI to measure cortical activation patterns associated with reading, and to examine the relationships of these measures to behavioral profiles and instructional outcomes; and (4) to examine whether intervention outcomes are related to behavioral and neurobiological differences among adolescent learners. Achieving these aims will not only have great potential benefit for the target population, but will also contribute to our understanding of: (a) the bases for adolescents' reading difficulties; (b) efficient and informative ways to assess the abilities and needs of struggling adolescent readers; (c) the similarities between reading problems of adolescents and those of younger children and of low-literate adults, at both the behavioral and neurobiological level; and (d) the consequences of growth in reading for functional brain organization.